table inheritance partition and indexes

I've created a table with a number of indexes and then created a partition table that inherits from it using "CREATE TABLE... INHERITS..." . I've then queried pg_indexes on the parent for its indexes and tried creating matching indexes on the child and attaching them to the parent table indexes. However "ALTER TABLE ... ATTACH PARTITION ..." is returning the error "<parent tables index name> is not a table partitioned index". I've followed the inheritance partitioning example and read the "CREATE INDEX" docs but I must be missing something, can anyone help me understand what I'm doing wrong? I'm using version 13.

Ted